Butterfly is a book-length single poem divided into three sections, each section containing untitled segments. Although the book is meant to be read in order, Butterfly is not a straight narrative; rather it is a lyric sequence grounded in the narrative circumstance of the deaths of a twin brother and mother. As such, the poem is an elegy, an exploration of grief within the particulars of both the twin dyad and the triad of mother and twins. Like all elegies, Butterfly is as much about the bereaved as the lost beloved, exploring family memories and mysteries of loyalty, conflict, love, and identity within the context of one family member's tragic self-destruction.

"In Butterfly, Diane Kerr writes: Inside of her/I could not tell/where he, one soft side,//left off, and I,/the other half, began./Curled back to back//we made a butterfly. In this utterly poignant and memorable sequence of poems, Kerr writes about her twin brother's death.
In stunning images of doubling and intimacy that return and return anew, these poems give a kind of life to unbearable loss: first to lie alone stone still,/first to wear a mound of wilting bloom...This is a writer whose courageous voice cuts through time and sorrow to find the undeniably true." -Jan Beatty

"Twins are more almost each other than are lovers, or mothers and babies. That almost-each-otherness evinces, in this book, a mysterious connection despite that one twin is an alcoholic. He was the strong one; he wrecked himself with vigor. Meanwhile, the one who feels she should have died, lives. This twin is the splint, 'sistering' the weak foundational wall of their life. But she is the strong one-strong as the wall between ventricles, and she sings this elegy, which is full of the ecstasy of grief. Kerr holds loss and transcendence in each hand, returning the present to us in the form of a golden pup. Like James Wright's horses, it reminds us that loneliness and joy can happen-unlikely twins-in a single moment."-Joy Katz

"Eudora Welty says in her essay on Henry Green: 'Virtuosity, unless it move the heart, goes at the head of the whole parade to dust.' Adding immediately, 'With Henry Green we always come back to this: this work is so moving.' So is Diane Kerr's. Her meticulous poetic skill is used relentlessly in the service of the heart. Butterfly renders intimate unanswerable human grief with grace, intelligence, beauty, and wisdom."-Michael Ryan

"We lavish whole childhoods on our siblings-and they on us. If we lose them, we lose an essential part of ourselves; vestiges of their beings remain with us as no others do. Diane Kerr examines, displays, and evokes this intense dynamic in her magnificently delicate sequence about fraternal twins, Butterfly. Without sentimentality and with genuine grace, Kerr summons up that shared womb and childhood with all the particularity and angst that made two beings so constitutionally different-and unequal-yet connected with a fathomless depth. In language detailed, mythic and arresting, Kerr makes the ineffable palpable in these tenderly crafted poems of fierce attachments."-Molly Peacock